Genetic predisposition to lung adenocarcinoma among never-smoking Chinese with different epidermal growth factor...

The inconsistent findings from genetic association studies may be related to the heterogeneity in different molecular subtypes of lung cancer. This study evaluated the predisposing single-nucleotide polymorphisms (SNPs) in epidermal growth factor receptor (EGFR) mutant and EGFR wild-type lung adenocarcinoma separately among never-smokers.

This was a two-stage case-control study. Never-smokers with pathologically confirmed lung adenocarcinoma and healthy controls were recruited in Hong Kong and Macau. Genomic DNA was extracted and genotyped by MassARRAY. In the discovery stage, 51 SNPs were investigated at the SNP, gene and pathway level among 103 EGFR mutant and 78 EGFR wild-type lung adenocarcinoma cases compared with matched controls. In the validation stage, SNPs that were identified with significant lung cancer risk were replicated in a separate cohort of 84 lung adenocarcinoma cases and compared with 103 Chinese Han, Beijing and 105 Chinese Han, Southern public controls from the 1000 genome database.

The genetic association of IL-6 rs2069840 with EGFR mutant lung adenocarcinoma was ascertained. In the discovery stage, haplotype GGG in three SNPs (rs2069840, rs2069852, rs2066992) of IL-6, synergetic effects of IL-6 rs2069840 and environmental tobacco smoke in the workplace were found to be related to EGFR mutant lung adenocarcinoma. ERCC2 rs238406 showed a marginally significant association with EGFR mutant lung adenocarcinoma in the validation stage (P=0.096). ERCC2 rs50871 and ATM rs611646 showed significant association with EGFR wild-type lung adenocarcinoma in the discovery stage. In conclusion, IL-6 rs2069840 conferred susceptibility to EGFR mutant lung adenocarcinoma in a Hong Kong and Macau never-smoking Chinese population.